An endocrine disruptor chemical (EDC) is an exogenous substance that impacts at least one function of an animal's endocrine system and consequently causes adverse health effects in an intact organism, its progeny, or (sub)populations. EDCs can cause adverse biological effects in animals and humans (Diamanti-Kandarakis et al., Horm. Metab Res 42:543-552, 2010).
Contamination of the environment, particularly water sources, with EDCs is a major concern for human health and threatens the integrity of aquatic ecosystems (Diamanti-Kandarakis et al., Endocr. Rev. 30:293-342, 2009; Deblonde et al., Int. J Hyg. Environ. Health 214:442-448, 2011). Harmful effects of synthetic progestogens (Zeilinger et al., Environ. Toxicol. Chem. 28:2663-2670, 2009; Paulos et al., Aquat. Toxicol. 99:256-262, 2010) and especially of estrogenic water contaminants (Iwanowicz et al., Environ. Toxicol. Chem. 28:1072-1083, 2009; Alvarez et al., Environ. Toxicol. Chem. 28:1084-1095, 2009; Caldwell et al., Environ. Sci. Technol. 42:7046-7054, 2008; Lange et al., Environ. Toxicol. Chem. 20:1216-1227, 2001; Blazer et al., Environ. Monit. Assess. DOI 10.1007/s10661-011-2266-5, 2011) on fish reproduction are well documented. In addition, there is growing concern that environmental contamination with EDCs has deleterious effects on human reproduction, breast development and cancer, prostate cancer, neuroendocrinology, thyroid metabolism and obesity, and cardiovascular endocrinology (Diamanti-Kandarakis et al., Endocr. Rev. 30:293-342, 2009).
Glucocorticoids act through the glucocorticoid and mineralocorticoids receptors (GR and MR, respectively). Glucocorticoid deficiency is associated with a number of complex symptoms and is a life-threatening condition (Arlt & Allolio, Lancet 361:1881-1893, 2003). Naturally occurring glucocorticoids are released in mammalian organisms during the circadian cycle. However, excess exposure to glucocorticoids is associated with immune suppression and variety of other deleterious side effects (Schacke et al., Pharmacol. Ther. 96:23-43, 2002). Unoccupied glucocorticoid receptor resides in the cytoplasm and is bound to various heat-shock proteins and immunophilins in a large multi-protein complex (Pratt & Toft, Endocr. Rev. 18:306-360, 1997; Pratt et al., Handb. Exp. Pharmacol. 172:111-138, 2006). Upon hormone binding, GR dissociates from the chaperones and translocates to the cell nucleus, where it interacts with GR regulatory elements (GREs) and elicits GR-specific transcription regulation (John et al., Mol. Cell 29:611-624, 2008).
At present, nothing is known about the prevalence of GCs activity in US water sources. However, using chemical methods, a few reports on water contamination in the Netherlands and China have demonstrated detectable levels of glucocorticoids (Schriks et al., Environ. Sci. Technol. 44:4766-4774, 2010; Change et al., Environ. Sci. Technol. 41:3462-3468, 2007). Another recent study has demonstrated that environmentally relevant concentrations of synthetic GCs have deleterious effects on fish (Kugathas & Sumpter, Environ. Sci. Technol. 45:2377-2383, 2011). The anti-inflammatory properties of the glucocorticoids make them highly prescribed pharmaceuticals. They could readily enter water sources and there are few sparse reports on water contamination with glucocorticoids (Schriks et al., Environ. Sci. Technol. 44:4766-4774, 2010; Chang et al., Environ. Sci. Technol. 41:3462-3468, 2007). Moreover, waste water treatment plants (WWTP) are not capable of efficiently removing glucocorticoids; it is well documented that anti-inflammatory chemicals are among the most resistant to treatment (30-40% of removal rate).
In spite of their importance, the levels of EDCs, such as steroidal EDCs, in the environment currently are not efficiently monitored and/or regulated. One of the reasons is that no high-throughput, reliable, low-cost detection methods exist for monitoring of biologically active EDCs. Current EDC detection relies on chemical analysis techniques (e.g., mass spectrometry, HPLC, GC, and other purely chemical analytical procedures), in vitro biologically-based but cell-free analysis techniques (e.g., purified receptor binding assays and immunoaffinity chromatography), in vitro cell-based analyses (e.g., cell proliferation assays and receptor-dependent gene expression assays, in human cells, or engineered yeast or bacterial cells), and in vivo analyses (e.g., uterotrophic and other growth/development assays in live rats or other animals). It is crucial to develop and implement novel high-throughput and low-cost methods for detection of EDCs in the environment. The need of such methods is well recognized in the field (Roy et al., J. Exp. Biol. 43:975-992, 2005). Existing methods for EDC detection may be sensitive, and in some instances are specific for individual ligands, but in general they are expensive, time-consuming, and largely incompatible with a large-scale sample testing.